The present invention relates to a vinyl chloride resin composition, and more particularly to a vinyl chloride resin composition having an improved impact resistance with an excellent transparency that the vinyl chloride resin itself possesses originally.
A so-called MBS resin wherein methyl methacrylate, styrene and the like are graft-polymerized onto a butadiene rubber has been used as a reinforcing agent for improving the impact resistance of vinyl chloride resins. It is important that the transparency of the resins is not impaired by the incorporation of the reinforcing agent. Various improvements of the reinforcing agent for vinyl chloride or of the process for improving the impact resistance of vinyl chloride resins without impairing the transparency of the resins are also proposed. However, demand for improvement of the quality of vinyl chloride resin products is still strong and a further improvement is desired.
For instance, it has been well known that the impact strength of the MBS resin is improved by agglomerating the particles to form large particles. Accordingly, various agglomerating techniques of the MBS resin particles have been developed, as discussed in, for instance, Japanese Examined Patent Publication No. 42-22541, and No. 46-3 1462, and the like. However, it is general that when the MBS resin having a large particle size is admixed with the vinyl chloride resin, the obtained vinyl chloride resin composition is lowered in transparency. As mentioned above, it is very difficult to obtain both a high impact resistance and a good transparency, the two properties being very important properties of the vinyl chloride resin composition.
An object of the present invention is, while adopting the method wherein the particle size of the MBS resin is increased as a means for markedly increasing the impact resistance imparting ability of the reinforcing agent (MBS resin) for the vinyl chloride resin, to solve the great defect of the method that the transparency is lowered.
A further object of the present invention is to provide a vinyl chloride resin composition having both a high impact resistance and an excellent transparency.
These and other objects of the present invention will become apparent from the description hereinafter.